KVM: MMU: abstract invalid guest pte mapping

Introduce a common function to map invalid gpte

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 37 insertions, 34 deletions

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 60f00dbe327a..a43f4ccd30bb 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -299,25 +299,42 @@ static int FNAME(walk_addr_nested)(struct guest_walker *walker,
                                         addr, access);
 }
 
+static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu,
+                                    struct kvm_mmu_page *sp, u64 *spte,
+                                    pt_element_t gpte)
+{
+        u64 nonpresent = shadow_trap_nonpresent_pte;
+
+        if (is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL))
+                goto no_present;
+
+        if (!is_present_gpte(gpte)) {
+                if (!sp->unsync)
+                        nonpresent = shadow_notrap_nonpresent_pte;
+                goto no_present;
+        }
+
+        if (!(gpte & PT_ACCESSED_MASK))
+                goto no_present;
+
+        return false;
+
+no_present:
+        drop_spte(vcpu->kvm, spte, nonpresent);
+        return true;
+}
+
 static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
                               u64 *spte, const void *pte)
 {
         pt_element_t gpte;
         unsigned pte_access;
         pfn_t pfn;
-        u64 new_spte;
 
         gpte = *(const pt_element_t *)pte;
-        if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) {
-                if (!is_present_gpte(gpte)) {
-                        if (sp->unsync)
-                                new_spte = shadow_trap_nonpresent_pte;
-                        else
-                                new_spte = shadow_notrap_nonpresent_pte;
-                        __set_spte(spte, new_spte);
-                }
+        if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
                 return;
-        }
+
         pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
         pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
         if (gpte_to_gfn(gpte) != vcpu->arch.update_pte.gfn)
@@ -364,7 +381,6 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
                                 u64 *sptep)
 {
         struct kvm_mmu_page *sp;
-        struct kvm_mmu *mmu = &vcpu->arch.mmu;
         pt_element_t *gptep = gw->prefetch_ptes;
         u64 *spte;
         int i;
@@ -395,16 +411,7 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
 
                 gpte = gptep[i];
 
-                if (is_rsvd_bits_set(mmu, gpte, PT_PAGE_TABLE_LEVEL))
-                        continue;
-
-                if (!is_present_gpte(gpte)) {
-                        if (!sp->unsync)
-                                __set_spte(spte, shadow_notrap_nonpresent_pte);
-                        continue;
-                }
-
-                if (!(gpte & PT_ACCESSED_MASK))
+                if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
                         continue;
 
                 pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
@@ -761,7 +768,6 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
                 pt_element_t gpte;
                 gpa_t pte_gpa;
                 gfn_t gfn;
-                bool rsvd_bits_set;
 
                 if (!is_shadow_present_pte(sp->spt[i]))
                         continue;
@@ -773,18 +779,15 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
                         return -EINVAL;
 
                 gfn = gpte_to_gfn(gpte);
-                rsvd_bits_set = is_rsvd_bits_set(&vcpu->arch.mmu, gpte,
-                                                 PT_PAGE_TABLE_LEVEL);
-                if (rsvd_bits_set || gfn != sp->gfns[i] ||
-                      !is_present_gpte(gpte) || !(gpte & PT_ACCESSED_MASK)) {
-                        u64 nonpresent;
-
-                        if (rsvd_bits_set || is_present_gpte(gpte) ||
-                              sp->unsync)
-                                nonpresent = shadow_trap_nonpresent_pte;
-                        else
-                                nonpresent = shadow_notrap_nonpresent_pte;
-                        drop_spte(vcpu->kvm, &sp->spt[i], nonpresent);
+
+                if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) {
+                        kvm_flush_remote_tlbs(vcpu->kvm);
+                        continue;
+                }
+
+                if (gfn != sp->gfns[i]) {
+                        drop_spte(vcpu->kvm, &sp->spt[i],
+                                      shadow_trap_nonpresent_pte);
                         kvm_flush_remote_tlbs(vcpu->kvm);
                         continue;
                 }